Pavlyuchenko, who joined the London club from Spartak Moscow at the end of August in a reported $28 million deal, was making his third appearance for Tottenham.
His goal, which came a day after he was mocked in the English press over statements expressing his shock at the intensity of training at Tottenham, came in the 62nd minute, the Russian rising well to direct a powerful header past Shay Given in the Newcastle goal.
Carling Cup holders Tottenham, currently propping up the English Premier League table, added another goal in the 66th minute, Jamie O'Hara capitalizing on a mistake in the Newcastle defense.
"Things were not going very well, but this victory has given us some peace of mind," said Tottenham manager Juande Ramos.
Gus Poyet, Tottenham's first team coach, said he was sure Pavlyuchenko would now go on to play "better and better."
"He had a chance, and he took it," he said.
